In general, mounting devices for boat sonar transducers fall into one of two categories: the devices either attach directly to the transom of the boat or hook over the upper ledge of the transom.
The first type of holder, as found in U.S. Pat. Nos. 3,714,619, issued to Morgan et. al., and 3,729,162, issued to Salvato, requires the mounting bracket to be either bolted or screwed to the transom. Such a transducer holder, however, has two distinct disadvantages. First, it necessitates the drilling of holes directly into the boat. And secondly, the holder is not easily removable which makes it both difficult to adjust and non-transportable.
The second type of holder provides for a more flexible means of supporting a transducer. One such device, as described in U.S. Pat. No. 3,989,213, issued to Allen, consists of a top portion which hooks over the upper ledge of the transom and is attached to a mounting post, the opposite end of which is a clamp that holds the transducer in depth-sensing position. The entire mounting device can be easily removed from the boat by pulling up on the attached handle.
Another such device, as shown in U.S. Pat. No. 3,752,431, issued to McBride, also has a bracket at the top which hooks over the upper ledge of the transom and a bracket at the bottom to which the transducer is bolted and held below the water line. This type of holder also has a crank arm to adjust the depth of the transducer.
Still another such device is set forth in the Blomberg U.S. Pat. No. 5,016,225. Again, the holder consists of an elongated base with an upper portion that hooks directly over the transom. This device also has a hollow cylindrical conduit that receives and protects the transducer lead, with the transducer being riveted to the base of the conduit. The conduit is held against the elongated base by thumb screws attached to mounting blocks; this arrangement also allows the entire conduit to be vertically moved to adjust the depth of the transducer.
This second category of transducer holder offers several advantages over the first type. The latter type does not require the drilling of holes into the boat hull, preventing permanent damage and making such a device more easy to install and remove. In addition, at least two of the second type are designed to be vertically adjustable, a task accomplished with the former type of holder only by removing the entire device and drilling new holes.
But even though the second category of transducer holder solves some of the problems associated with the first type, it does not fulfill all of the needs of the typical boater. All of the devices mentioned so far in general only set forth a means for holding the sonar transducer below the water line. A complete embodiment of a transducer holder should not only perform the function of holding the transducer but should also provide a means for supporting the depth-finder itself. Such a device would thus keep the depth-finder and transducer in one convenient location on a boat.